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Oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule (the reductant, electron donor) to another (the oxidant,electron acceptor). This enzyme is part of a group of enzymes commonly known as dehydrogenases or oxidases. The fuction of these enzymes is to catalyze the removal of hydrogen atoms and electrons from the compounds on which they act. Substances called coenzymes, associated with the oxidoreductase enzymes and necessary for their activity, these substances accept the hydrogen and electrons, which via the progress of the metabolic systems of animals will eventually be transferred to oxygen. Other enzymes of this group catalyze such reactions as the oxidation of aldehydes and ketones to carboxylic acids and the dehydrogenation of amino acids. This is how the reaction proceeds an enzyme that catalyzed this reaction [A(minus) + B(neutral) → A(neutral) + B(minus)] would be an oxidoreductase:

In this example, A is the reductant (electron donor) and B is the oxidant (electron acceptor).Now in biochemical reactions, an example of this kind of reaction would be this partial reaction from glycolysis: Pi + glyceraldehyde-3-phosphate + NAD+ → NADH + H+ + 1,3-bisphosphoglycerate

The triose sugars are dehydrogenated and inorganic phosphate is added to them, forming 1,3-bisphosphoglycerate.

The hydrogen is used to reduce two molecules of NAD+, a hydrogen carrier, to give NADH(dehydrogenase is an enzyme witch is used fo trasport of electrons) + H+ for each triose. Hydrogen atom balance and charge balance are both maintained because the phosphate (Pi) group actually exists in the form of a hydrogen phosphate anion (HPO42-) which laterr dissociates to contribute the extra H+ ion and gives a net charge of -3 on both sides.

In this reaction, NAD+ is the oxidant (electron acceptor), and glyceraldehyde-3-phosphate is the reductant (electron donor)

References: 1.http://en.wikipedia.org/wiki/Oxidoreductase 2.http://www.britannica.com/EBchecked/topic/436732/oxidoreductase 3.http://en.wikipedia.org/wiki/Glycolysis 4.http://en.wikipedia.org/wiki/NADH_dehydrogenase

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